A half transparent or hybrid type liquid crystal display (LCD) device includes a thin film transistor (TFT) array substrate, which is, in turn, provided with reflective and transparent display portions. The reflective display portion is generally made of thin film transistors formed on the TFT array substrate, an insulation film covering the thin film transistors and reflective electrodes formed on the insulation film. The transparent display portion is, on the other hand, made of the insulation film and transparent electrodes. The insulation film of the reflective display portion is different in thickness from that of the transparent display portion to increase the reflectivity and transmittance of the reflective and transparent display portions, respectively. In addition, when the TFT array substrate is put together with a counter substrate, the cell gaps defined in the reflective and transparent display portions are configured to be optimal, respectively. In order to adjust such thickness difference between the reflective and transparent display portions, a photoresist is coated on both the reflective and transparent display portions of the TFT array substrate, the transparent display portion is subjected to an optical exposure treatment, and both reflective and transparent display portions are developed and post-baked.
Since a photoresist with high transmittance is, however, used for the insulation film, it is subjected to reflecting light from an exposure stage during the exposure treatment.
As shown in FIG. 5, an optical exposure stage 210 is provided with recesses 212, which are used to set a TFT array substrate on the exposure stage 210 or to detach it from the stage 210, and plates 214. Although the recesses 212 do not reflect incident light, the plates 214 reflect it as shown by dotted lines and arrows. Thus, portions of an insulation film 128 corresponding to the recesses 212 receive incident light passing through a photomask 208. The other portions of the insulation film 128 corresponding to the plates 214, however, receive not only incident light passing through the photomask 208 but also reflecting light from the plates 214. Since pattern dimensions depend on a received quantity of light, patterns of the portions positioned above the recesses 212 are small in width but those of the portions positioned above the plates 214 are wide in width though not shown in different widths in FIG. 5. Such different widths in the patterns cause visibly uneven brightness of images displayed by an LCD device.